Generally, a cold crucible induction melter (CCIM) has a cylindrical melting chamber which comprises a plurality of metal sectors along which coolant circulates. The metal sectors are insulated by insulators interposed therebetween. A high-frequency induction coil is provided outside the melting chamber to provide power required to melt a substance contained in the melting chamber.
Representative examples of cold crucible induction melters in which metal sectors form a wall of a melter and electrical insulators are interposed between the metal sectors were proposed in U.S. Pat. No. 4,923,508 (Date of patent: May 8, 1990), No. 4,738,713 (Date of patent: Apr. 19, 1988), and No. 6,996,153 (Date of patent: Feb. 7, 2006).
In such a cold crucible induction melter, high-frequency current is applied to an induction coil to melt a substance in the melter. The wall of the melter includes a plurality of metal sectors which are insulated by the insulators to restrict induced current and ensure relative penetrability of an electromagnetic field.
Furthermore, each metal sector is cooled by circulation of coolant to maintain the wall of the melter at a predetermined temperature. During a vitrification process of waste, molten glass which makes contact with the wall of the melter is solidified, thus forming a thin layer so that the sealing performance of the melter is ensured.
As such, the metal sector is made of metal which has electromagnetic field penetrability, but metal causes generation of heat from induction current, resulting in a reduction of operational efficiency of the melter.
To avoid these problems, the metal sector must restrict induced current and prevent an electric arc from being generated between the metal sectors.
Given this, the shape of the metal sector is designed such that the size thereof is as small as possible to minimize generation of induced current, or to prevent an electric arc from being generated. Typically, the cross-sectional shape of the metal sector is rhomboidal or trapezoidal, and corners of the metal sector are rounded.